So, should married men have control of the investments? Several studies say no. University researchers Brad Barber and Terrance Odean studied 35,000 household brokerage accounts between 1991 and 1997. Women’s portfolios beat men’s by nearly three percent per year on a risk-adjusted basis.

A 2005 Merrill Lynch investment survey says men make more mistakes. Fewer men diversify. They also trade more often than women do. That increases transaction costs and taxable liabilities. The study identified the same differences as the Barber and Odean study. Men’s returns are lower, Barber and Odean speculated, due to “over-confidence.”

Over the five-year period that ended in 2014, men averaged a compound annual return of 10.1 percent year. Women averaged a compound annual return of 9.7 percent. Other studies say that men take higher risks. But Vanguard’s data might dump that assumption. In 2014, the average male Vanguard investor had 26 percent in bonds, 64 percent in stocks. The average woman had 27 percent in bonds, 63 percent in stocks.

Vanguard’s investors, however, might not be typical. Most of them invest in index funds. Across the board, such investors tend to be far more disciplined than the typical investor in actively managed funds.

But Brian Thompson says we shouldn’t bother asking whether men or women are better at investing. There’s a much bigger issue. He’s a Certified Financial Planner with Brian Thompson Financial in Chicago, Illinois. He specializes in financial planning for gay and lesbian couples. “Often, one spouse handles all of the finances,” he says, “and the other sticks their head in the sand. I find that when they start to work together, they make better headway.”

People start by answering a series of online questions. The program identifies their top 5 strengths out of a possible 34. These strengths have names like Activator, Maximizer, Discipline and Learner. Once determined, they allow people to better understand their natural thoughts and behaviors.

“When investing, couples should have an intimate understanding of each partner’s strengths,” says Aleasha. It helps them to make better decisions together. She adds, “One partner might have Activator or Maximizer strengths. They tend to pull the trigger on novel opportunities because they’re excited and energized when there’s movement.”

He works for Olympia Ridge-Personal Financial Advisers. Scott says that when a dominant partner is quick to pull the trigger, the couple can run into problems. "It usually leads to poor long-term investment performance.”

Couples rarely have the same strengths. Aleasha Morris says that’s fine. “Assume that the other partner’s top strengths are Discipline and Learner. They usually prefer methodical approaches to investing. That might mean a low risk, proven performance option.” But such investors need to talk to their partners. Those who don’t could end up sitting on their butts and not taking action.

Scott Smith says that without a gentle push, those non-invested assets will lose money to inflation.

He explains, “The couples I see who are most financially effective communicate about money. I recommend that couples pick one day a month to discuss their household finances. They may not agree with one another, but at least they are talking.”

It sounds like married men and women–no matter how financially savvy–should avoid investing solo when they have a co-pilot.

This article contains the opinions of the author but not necessarily the opinions of AssetBuilder Inc. The opinion of the author is subject to change without notice. All materials presented are compiled from sources believed to be reliable and current, but accuracy cannot be guaranteed. This article is distributed for educational puposes, and it is not to be construed as an offer, solicitation, recommendation, or endorsement of any particular security, product, or service.

Performance data shown represents past performance. Past performance is no guarantee of future results and current performance may be higher or lower than the performance shown.

AssetBuilder Inc. is an investment advisor registered with the Securities and Exchange Commission. Consider the investment objectives, risks, and expenses carefully before investing.